#include <algorithm>
#include <cfloat>
#include <vector>

#include "caffe/layers/softmax_hard_boostrap_loss_layer.hpp"
#include "caffe/util/math_functions.hpp"

namespace caffe {

template <typename Dtype>
void SoftmaxWithHardBoostrapLossLayer<Dtype>::LayerSetUp(
    const vector<Blob<Dtype>*>& bottom, const vector<Blob<Dtype>*>& top) {
  LossLayer<Dtype>::LayerSetUp(bottom, top);
  LayerParameter softmax_param(this->layer_param_);
  softmax_param.set_type("Softmax");
  softmax_layer_ = LayerRegistry<Dtype>::CreateLayer(softmax_param);
  softmax_bottom_vec_.clear();
  softmax_bottom_vec_.push_back(bottom[0]);
  softmax_top_vec_.clear();
  softmax_top_vec_.push_back(&prob_);
  softmax_layer_->SetUp(softmax_bottom_vec_, softmax_top_vec_);

  has_ignore_label_ =
    this->layer_param_.loss_param().has_ignore_label();
  if (has_ignore_label_) {
    ignore_label_ = this->layer_param_.loss_param().ignore_label();
  }
  if (!this->layer_param_.loss_param().has_normalization() &&
      this->layer_param_.loss_param().has_normalize()) {
    normalization_ = this->layer_param_.loss_param().normalize() ?
                     LossParameter_NormalizationMode_VALID :
                     LossParameter_NormalizationMode_BATCH_SIZE;
  } else {
    normalization_ = this->layer_param_.loss_param().normalization();
  }
  beta_ = this->layer_param_.loss_param().beta();
}

template <typename Dtype>
void SoftmaxWithHardBoostrapLossLayer<Dtype>::Reshape(
    const vector<Blob<Dtype>*>& bottom, const vector<Blob<Dtype>*>& top) {
  LossLayer<Dtype>::Reshape(bottom, top);
  softmax_layer_->Reshape(softmax_bottom_vec_, softmax_top_vec_);
  softmax_axis_ =
      bottom[0]->CanonicalAxisIndex(this->layer_param_.softmax_param().axis());
  outer_num_ = bottom[0]->count(0, softmax_axis_);
  inner_num_ = bottom[0]->count(softmax_axis_ + 1);
  max_id_.Reshape(bottom[1]->shape());
  CHECK_EQ(outer_num_ * inner_num_, bottom[1]->count())
      << "Number of labels must match number of predictions; "
      << "e.g., if softmax axis == 1 and prediction shape is (N, C, H, W), "
      << "label count (number of labels) must be N*H*W, "
      << "with integer values in {0, 1, ..., C-1}.";
  if (top.size() >= 2) {
    // softmax output
    top[1]->ReshapeLike(*bottom[0]);
  }
}

template <typename Dtype>
Dtype SoftmaxWithHardBoostrapLossLayer<Dtype>::get_normalizer(
    LossParameter_NormalizationMode normalization_mode, int valid_count) {
  Dtype normalizer;
  switch (normalization_mode) {
    case LossParameter_NormalizationMode_FULL:
      normalizer = Dtype(outer_num_ * inner_num_);
      break;
    case LossParameter_NormalizationMode_VALID:
      if (valid_count == -1) {
        normalizer = Dtype(outer_num_ * inner_num_);
      } else {
        normalizer = Dtype(valid_count);
      }
      break;
    case LossParameter_NormalizationMode_BATCH_SIZE:
      normalizer = Dtype(outer_num_);
      break;
    case LossParameter_NormalizationMode_NONE:
      normalizer = Dtype(1);
      break;
    default:
      LOG(FATAL) << "Unknown normalization mode: "
          << LossParameter_NormalizationMode_Name(normalization_mode);
  }
  // Some users will have no labels for some examples in order to 'turn off' a
  // particular loss in a multi-task setup. The max prevents NaNs in that case.
  return std::max(Dtype(1.0), normalizer);
}

template <typename Dtype>
void SoftmaxWithHardBoostrapLossLayer<Dtype>::Forward_cpu(
    const vector<Blob<Dtype>*>& bottom, const vector<Blob<Dtype>*>& top) {
  LOG(FATAL) << "CPU version for SoftmaxWithHardBoostrapLoss is not implemented";
  // The forward pass computes the softmax prob values.
  //softmax_layer_->Forward(softmax_bottom_vec_, softmax_top_vec_);
  //const Dtype* prob_data = prob_.cpu_data();
  //const Dtype* label = bottom[1]->cpu_data();
  //int dim = prob_.count() / outer_num_;
  //int count = 0;
  //Dtype loss = 0;
  //for (int i = 0; i < outer_num_; ++i) {
  //  for (int j = 0; j < inner_num_; j++) {
  //    const int label_value = static_cast<int>(label[i * inner_num_ + j]);
  //    if (has_ignore_label_ && label_value == ignore_label_) {
  //      continue;
  //    }
  //    DCHECK_GE(label_value, 0);
  //    DCHECK_LT(label_value, prob_.shape(softmax_axis_));
  //    loss -= log(std::max(prob_data[i * dim + label_value * inner_num_ + j],
  //                         Dtype(FLT_MIN)));
  //    ++count;
  //  }
  //}
  //top[0]->mutable_cpu_data()[0] = loss / get_normalizer(normalization_, count);
  //if (top.size() == 2) {
  //  top[1]->ShareData(prob_);
  //}
}

template <typename Dtype>
void SoftmaxWithHardBoostrapLossLayer<Dtype>::Backward_cpu(const vector<Blob<Dtype>*>& top,
    const vector<bool>& propagate_down, const vector<Blob<Dtype>*>& bottom) {
  LOG(FATAL) << "CPU version for SoftmaxWithHardBoostrapLoss is not implemented";
  //if (propagate_down[1]) {
  //  LOG(FATAL) << this->type()
  //             << " Layer cannot backpropagate to label inputs.";
  //}
  //if (propagate_down[0]) {
  //  Dtype* bottom_diff = bottom[0]->mutable_cpu_diff();
  //  const Dtype* prob_data = prob_.cpu_data();
  //  caffe_copy(prob_.count(), prob_data, bottom_diff);
  //  const Dtype* label = bottom[1]->cpu_data();
  //  int dim = prob_.count() / outer_num_;
  //  int count = 0;
  //  for (int i = 0; i < outer_num_; ++i) {
  //    for (int j = 0; j < inner_num_; ++j) {
  //      const int label_value = static_cast<int>(label[i * inner_num_ + j]);
  //      if (has_ignore_label_ && label_value == ignore_label_) {
  //        for (int c = 0; c < bottom[0]->shape(softmax_axis_); ++c) {
  //          bottom_diff[i * dim + c * inner_num_ + j] = 0;
  //        }
  //      } else {
  //        bottom_diff[i * dim + label_value * inner_num_ + j] -= 1;
  //        ++count;
  //      }
  //    }
  //  }
  //  // Scale gradient
  //  Dtype loss_weight = top[0]->cpu_diff()[0] /
  //                      get_normalizer(normalization_, count);
  //  caffe_scal(prob_.count(), loss_weight, bottom_diff);
  //}
}

#ifdef CPU_ONLY
STUB_GPU(SoftmaxWithHardBoostrapLossLayer);
#endif

INSTANTIATE_CLASS(SoftmaxWithHardBoostrapLossLayer);
REGISTER_LAYER_CLASS(SoftmaxWithHardBoostrapLoss);

}  // namespace caffe
